Community antenna television (“CATV”) networks have been used for more then four decades to deliver television programming to a large number of subscribers. Increasingly, CATV networks are used by providers to provide data services to subscribers. For example, operator managed devices, such as cable modems, used in a broadband cable modem termination system (“CMTS”) are capable of transmitting and receiving Internet data using the Data Over Cable Service Interface Specification (“DOCSIS”) protocol. DOCSIS provides a standard that allows network devices made by different vendors to communication with one another.
In addition to cable modem networks, where the modems are typically located at a customer's premises and a Cable Modem Termination System (“CMTS”) is located at an provider's/operator's head end location, Digital subscriber Line (“DSL”) technology is used by telephone companies to augment their ‘dial-up’ services to better compete with the cable companies broadband offerings. The telephone companies typically require that a user ‘log-in’ to the provider's network, either DSL or Dial-up, using Point-to-Point Protocol over Ethernet (“PPPoE”) technology.
In the United States, this typically gives the data over cable providers a competitive differentiator, in that a cable modem broadband connection is typically ‘always on’ when the modem has been turned on and booted up. Thus, customers do not have to manually log on to the provider's network.
However, outside of North America, many cable operators are part of a larger enterprise that provides Internet access via cable, DSL, and dial-up. Thus, operators typically manage the cable data service in the same way as the DSL and dial-up services. As such, access to the cable service is controlled via a PPPoE login client that is installed on each Customer Premise Equipment (“CPE”), such as a personal computer, for example. This is similar to the operator's DSL service configuration and thus is familiar to them.
In such an architectural arrangement 2, as shown in FIG. 1, the login client 4 communicates with a subscriber management server (“SMS”) 6 at the cable head end that authenticates the subscriber and logs session accounting records in a Remote Authentication Dial Up Server 10 (“RADIUS”), configures the IP settings of the client 4, and terminates the PPPoE tunnel to allow the encapsulated IP packets to be routed to their destination.
Turning now to FIG. 2, the configuration and subscriber login processes in a prior art system are illustrated to provide a comparison to the configuration and subscriber login pathways associated with system 18 as shown in FIG. 3, reference to which is discussed in detail below in the Detailed Description. In FIG. 2, when cable modem 16 boots up, it interacts with dynamic host configuration protocol (“DHCP”) server 14. After network access has been provided to modem 16 and logged by DHCP server 14, PPPoE client 4 establishes a session by sending login information, typically comprising a log in identifier and a password, to SMS 6. SMS 6 interacts with RADIUS server 10 to record session statistics therein. These statistics are later used for billing and other purposes as discussed above. While this multi-path, distributed login scheme is functional, it is inefficient because different servers are used for configuring and logging in the CM 16 and CPE client 4. In addition, the PPPoE client 4 encapsulates login data into Ethernet packets for communication with SMS 6. Thus, CMTS 12 is a layer-2 switch because after modem 16 is registered at step A, the CPE client 4 is authenticated through SMS 6 at step B, after which the SMS records the session in the RADIUS server 10 at step C. As discussed above, this allows the SMS to authenticate the client 4, so that a provider's operation can use a similar method for authenticating DSL, dial-up and cable subscribers. Thus, the same RADIUS server 10 can be used for all of a provider's customers.
The advantage to this architecture is that the PPP and RADIUS components are in common with the DSL and dial-up architecture. Thus, efficiency of the operator's subscriber accounting and billing are more efficient. Also, some countries have laws that require operators to provide subscriber-access-records to law enforcement authorities; RADIUS accounting records may be used for this as well.
The primary disadvantage to this architecture is that PPPoE encapsulates the IP packets between the client and the SMS in an Ethernet frame that must be forwarded via a Layer-2 switching CMTS 12. This effectively limits the operator to using older generation Layer-2 switching CMTSs 12 instead of using next-generation Layer-3 routing IP CMTSs that are the current state of the art in terms of wire-speed Quality of Service (“QoS”), high capacity and high availability. Furthermore, there is a significant performance penalty for the encapsulation of IP in PPPoE as SMS 6 must be capable of high performance encapsulation and routing of the IP traffic in the PPPoE tunnels for each client. An additional issue is that PPPoE encapsulated IP headers cannot be inspected by the DOCSIS 1.1 service flow classifiers and hence any benefits of per application QoS (especially VoIP) are not available to PPPoE clients.
As an alternative, if a Layer 2 Tunneling Protocol (“L2TP”) client is used for each subscriber (instead of a PPPoE client) to permit the use of PPP over a routing CMTS in the path, then the SMS performance is even further degraded. Another variation on this theme is for the routing CMTS 12 to perform a PPPoE-to-L2TP gateway function to allow the aggregation of the client PPP sessions into a single L2TP session to the SMS to reduce the performance impact on the SMS. However, this also imposes a significant performance penalty on the CMTS as the cost of the PPPoE encapsulation just moves from one device in the network to another.
Another disadvantage is that the DOCSIS architecture uses the DHCP protocol to configure the cable modems and it is available to be used to configure the CPE as well. A DHCP server 14 that is typically integrated into a more functional subscriber management package provided by third party vendors can handle the management of both of these devices. But when PPPoE is used in a DOCSIS cable data system, cable modems 16 are configured via DHCP in one device and the CPEs 4 are configured via PPPoE in yet another device. This creates unnecessary management costs and complexity for the cable operator.
Thus, there is a need in the art for a method and system that eliminates the need for PPPoE login in a cable modem data system. There is also a need in the art for a method and system that use layer-3 routing, rather than layer-2 switching.